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Date:   Mon, 11 Jul 2022 11:03:48 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, "Jason A . Donenfeld " <Jason@zx2c4.com>,
        bpf@vger.kernel.org
Subject: Re: [PATCH 2/2] crypto: make the sha1 library optional
Message-ID: <20220711110348.4c951fff@kernel.org>
In-Reply-To: <20220709211849.210850-3-ebiggers@kernel.org>
References: <20220709211849.210850-1-ebiggers@kernel.org>
        <20220709211849.210850-3-ebiggers@kernel.org>
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On Sat,  9 Jul 2022 14:18:49 -0700 Eric Biggers wrote:
> Since the Linux RNG no longer uses sha1_transform(), the SHA-1 library
> is no longer needed unconditionally.  Make it possible to build the
> Linux kernel without the SHA-1 library by putting it behind a kconfig
> option, and selecting this new option from the kconfig options that gate
> the remaining users: CRYPTO_SHA1 for crypto/sha1_generic.c, BPF for
> kernel/bpf/core.c, and IPV6 for net/ipv6/addrconf.c.
> 
> Unfortunately, since BPF is selected by NET, for now this can only make
> a difference for kernels built without networking support.

> diff --git a/init/Kconfig b/init/Kconfig
> index c984afc489dead..d8d0b4bdfe4195 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1472,6 +1472,7 @@ config HAVE_PCSPKR_PLATFORM
>  # interpreter that classic socket filters depend on
>  config BPF
>  	bool
> +	select CRYPTO_LIB_SHA1
>  

Let's give it an explicit CC: bpf@

> diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
> index bf2e5e5fe14273..658bfed1df8b17 100644
> --- a/net/ipv6/Kconfig
> +++ b/net/ipv6/Kconfig
> @@ -7,6 +7,7 @@
>  menuconfig IPV6
>  	tristate "The IPv6 protocol"
>  	default y
> +	select CRYPTO_LIB_SHA1
>  	help
>  	  Support for IP version 6 (IPv6).

FWIW:
Acked-by: Jakub Kicinski <kuba@kernel.org>